Many modern cars come equipped with keyless entry thanks to key fobs. However, some older models did not initially include this convenient feature. If your car did not come with keyless entry, fear not, as it is possible to retrofit your vehicle with an aftermarket key fob system. This article will explain the process of adding a key fob to a car that was not factory-equipped with one. From assessing your vehicle's compatibility to installation tips, by the end you will have the knowledge needed to upgrade your keys.
Does Your Car Support Aftermarket Key Fobs?
The first step is determining if your specific car make and model can support an aftermarket key fob system. Many auto parts stores have online tools to check compatibility. Input your vehicle information to see what plug-and-play systems are available. Compatibility depends on your car's electrical architecture, so it's important to ensure a proper fit.
Choosing the Right Key Fob System
Once you know aftermarket systems can work, research the options. Look at reviews to find reliable brands. Consider the number of keys, operating range, and included functions like remote start or trunk release. Longer-range systems may have more parts or complexity. Balance features with your technical abilities, since some require more wiring than others.
Installation Difficulty Will Vary
Installation difficulty varies depending on your vehicle and the system chosen. Some plug directly into wiring behind interior panels, while others involve more extensive wiring. Systems with fewer components generally install easier. Be prepared for jobs requiring disassembling interiors down to frames or adding relays under hoods. Research what's involved with your specific vehicle-system combo.
Gather Tools and Components
Before starting, gather all the included parts, instructions, and necessary tools. Common tools include screwdrivers, wire strippers, electrical tape, crimping tools, voltmeter and installation guides. Confirm you have everything shown in the diagrams. Also, gather fuses, connectors, butt splices, or relays if indicated. Double check extra steps if your vehicle bypasses theft deterrent systems or adds antenna wires.
Find a wiring diagram
Locate a factory wiring diagram for your vehicle in a service manual or online. This shows where to find accessories, power and ignition wires to connect the fob system. Tracing where these colored wires lead makes installation much more manageable than random probing. Photocopy or print diagrams to mark up as you work. Understanding your vehicle's electrical layout prevents accidental shorts or improper connections.
Plan the installation route
Look for existing routes wires can follow between components rather than drilling new holes. Grommets and passthrough locations allow bundling new wires with factory harnesses. Consider future serviceability if mounting control modules under dashes. Mark paths on diagrams. Always leave slack in wires for movement. Probe existing grommets with a stiff wire to avoid jamming before fishing new wiring through tight spots.
Remove panels carefully
Begin removing interior trim pieces and under-hood parts according to diagrams while maintaining proper order. Use plastic pry tools to prevent damage. Support heavier components unscrewed. Set aside hardware, keeping similar fasteners grouped. Keeping screws organized lets panel reinstallation mimic removal steps. Protect now-exposed areas with tape to avoid scratches during installation.
Connect Accessory Power Wire
Find constant 12V+ power on your vehicle, usually at the fuse panel. Attach one end of the accessory wire with a crimp or twist connector. Apply electrical tape. Route to the fob module location while avoiding moving parts. Confirm 12V+ at the module to power it even with the key out. Fused connections prevent wiring damage if accidentally grounded. Solder and heat-shrink professional installations.
Connect Ignition Trigger Wire
Trace the ignition wire from the ignition switch/ECU harness. It will have 12V+ only when the key is in the ON position. Strip and connect to the fob module's ignition input. Route neatly with accessory power. Sometimes, the reverse light wire works for remote start cutoffs. Test by verifying the module loses power when the key is out of ignition before moving on.
Antenna installation (if needed)
Some systems include an external antenna to boost the wireless range. Carefully drill holes and route coax where instructed. Mount the antenna away from noisier electronics like ignition coils. Connect to the fob module with included connectors or crimp splices. Ensure the antenna is properly grounded per instructions. Double check position, grounding and connectors before sealing for best reception.
Program Remote Fobs
Refer to specific FOB manuals for programming steps. Common methods involve putting the fob module into pairing mode by toggling a learn button or switch. Then, press buttons on key fobs individually until the module chirps or LED flashes to learn them. Save codes by cycling the learn switch. Test-programmed fobs work for locking, unlocking, and other functions before reassembly.
Reinstall Panels and Test
Replace removed components following the reverse of the removal order while carefully routing new wiring. Reuse existing clips, screws and fasteners. Snug, but do not overtighten to avoid damage. Test all functions of the added key fob system, such as locking, unlocking, remote start, trunk release and panic button. Check for glitches when starting the car with the new key. Re-tighten any loose connections found and troubleshoot as needed.
Adding convenience and value
A properly installed aftermarket keyless entry system brings the convenience of remote locking, unlocking and starting without delving into your car's electricals. With some research and care, most DIYers can complete such upgrades. Beyond ease of use, key fobs also retain or boost your vehicle's resale value. Enjoy your upgraded keyless functionality and the peace of mind from increased security.
Conclusion
With the right equipment and information, adding remote keyless functions to a car not originally equipped is very possible. Carefully planning the installation and taking your time ensures a tidy, reliable job. Key fobs significantly upgrade convenience at a low cost compared to original factory systems. Take before starting photos for reference as needed. With some basic skills, almost any driver can enhance their vehicle.
